Honestly for the price of a homemade one pal they're miles better and it is luck of the draw if they go wrong like anything electrical but I used to make and sell loads and maybe had a handful back and I'm certain they was more due to people miswiring them the wrong way round😂
I've had my current one in over a year now going strong still and I keep a spare in the van in case it ever went tits up while out working, its a 2 minute swap and back at it again😎
When I had a spring controller I had to come home start checking connections after I couldn't do a quick fix at the side of the rd and I found I was constantly recalibrating them too, these basic things use the pumps pressure switch to shut themselves off and you can adjust the pressure switch on most pumps anyway, I use mine with a shurflo pump.